It is only going to check the part of the drive used for that array. So on your 1TB drive with a 500GB partition allocated to the array only the 500GB part will be checked. Mdadm doesn't know about the rest of the drive and even if it did it is not like it can compare that space against anything. Ryan On Tue, Sep 22, 2009 at 11:38 AM, Jon Hardcastle <jd_hardcastle@xxxxxxxxx> wrote: > Some good suggestions here, thanks guys. > > Do I >DID< imagine some built in support for making use of this space? > > As a side note. when i do a repair or check on my array.. does it check the WHOLE DRIVE.. or just the part that is being used? I.e. in my case.. I have a 1TB drive but only an array multiple of 500GB.. i'd like to think it is checking the whole whack as it may have to take over some day... > > ----------------------- > N: Jon Hardcastle > E: Jon@xxxxxxxxxxxxxxx > 'Do not worry about tomorrow, for tomorrow will bring worries of its own.' > ----------------------- > > > --- On Tue, 22/9/09, Majed B. <majedb@xxxxxxxxx> wrote: > >> From: Majed B. <majedb@xxxxxxxxx> >> Subject: Re: Full use of varying drive sizes? >> To: "Linux RAID" <linux-raid@xxxxxxxxxxxxxxx> >> Date: Tuesday, 22 September, 2009, 2:07 PM >> When I first put up a storage box, it >> was built out of 4x 500GB disks, >> later on, I expanded to 1TB disks. >> >> What I did was partition the 1TB disks into 2x 500GB >> partitions, then >> create 2 RAID arrays: Each array out of partitions: >> md0: sda1, sdb1, sdc1, ...etc. >> md1: sda2, sdb2, sdc2, ...etc. >> >> All of those below LVM. >> >> This worked for a while, but when more 1TB disks started >> making way >> into the array, performance dropped because the disk had to >> read from >> 2 partitions on the same disk, and even worse: When a disk >> fail, both >> arrays were affected, and things only got nastier and worse >> with time. >> >> I would not recommend that you create arrays of partitions >> that rely >> on each other. >> >> I do find the JBOD -> Mirror approach suggested earlier >> to be convenient though. >> >> On Tue, Sep 22, 2009 at 3:58 PM, John Robinson >> <john.robinson@xxxxxxxxxxxxxxxx> >> wrote: >> > On 22/09/2009 12:52, Kristleifur Dađason wrote: >> >> >> >> On Tue, Sep 22, 2009 at 11:24 AM, Jon Hardcastle >> >> <jd_hardcastle@xxxxxxxxx> >> wrote: >> >>> >> >>> Hey guys, >> >>> >> >>> I have an array made of many drive sizes >> ranging from 500GB to 1TB and I >> >>> appreciate that the array can only be a >> multiple of the smallest - I use the >> >>> differing sizes as i just buy the best value >> drive at the time and hope that >> >>> as i phase out the old drives I can '--grow' >> the array. That is all fine and >> >>> dandy. >> >>> >> >>> But could someone tell me, did I dream that >> there might one day be >> >>> support to allow you to actually use that >> unused space in the array? Because >> >>> that would be awesome! (if a little hairy re: >> spare drives - have to be the >> >>> size of the largest drive in the array >> atleast..?) I have 3x500GB 2x750GB >> >>> 1x1TB so I have 1TB of completely unused >> space! >> >> >> >> Here's a thought: >> >> Imaginary case: Say you have a 500, a 1000 and a >> 1500 GB drive. You >> >> could JBOD the 500 and the 1000 together and >> mirror that against the >> >> 1500GB. >> >> >> >> Disclaimer: >> >> I don't know if it makes any sense to do this. I >> haven't seen this >> >> method mentioned before, IIRC. It may be too >> esoteric to get any >> >> press, or it may be simply stupid. >> > >> > Sure you can do that. In Jon's case, a RAID-5 across >> all 6 discs using the >> > first 500GB, leaving 2 x 250GB and 1x 500GB free. The >> 2 x 250GB could be >> > JBOD'ed together and mirrored against the 500GB, >> giving another 500GB of >> > usable storage. The two md arrays can in turn be >> JBOD'ed or perhaps better >> > LVM'ed together. >> > >> > Another approach would be to have another RAID-5 >> across the 3 larger drives, >> > again providing an additional 500GB of usable storage, >> this time leaving 1 x >> > 250GB wasted, but available if another 1TB drive was >> added. I think this may >> > be the approach Netgear's X-RAID 2 takes to using >> mixed-size discs: >> > http://www.readynas.com/?p=656 >> > >> > Cheers, >> > >> > John. >> > -- >> > To unsubscribe from this list: send the line >> "unsubscribe linux-raid" in >> > the body of a message to majordomo@xxxxxxxxxxxxxxx >> > More majordomo info at http://vger.kernel.org/majordomo-info.html >> > >> >> >> >> -- >> Majed B. >> -- >> To unsubscribe from this list: send the line "unsubscribe >> linux-raid" in >> the body of a message to majordomo@xxxxxxxxxxxxxxx >> More majordomo info at http://vger.kernel.org/majordomo-info.html >> > > > > -- > To unsubscribe from this list: send the line "unsubscribe linux-raid" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html > -- To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
